1. Field of the Invention
The present invention relates to an image forming apparatus having a power-saving mode, a method for controlling the image forming apparatus, and a program.
2. Description of the Related Art
Recent image forming apparatuses capable of operating as multifunctional devices having a plurality of functions have become mainstream. The apparatuses are provided with a copying function for printing information read from original documents, and further provided with a function for storing image information, a function for sending and receiving electronic data via a public line or a network, and the like.
Meanwhile, there are growing needs for reducing power consumption, especially, if an apparatus is not in operation for a predetermined time, it is expected that the apparatus enters into a power saving state.
With the increasing number of functions, processes for enabling the functions are added to the image forming apparatuses. This inevitably increases the startup time of the apparatuses from power activation to an operable state.
To solve the problem, Japanese Patent Application Laid-Open No. 2004-38546 discusses an application of a hibernation technology to an image forming apparatus.
In the application of the hibernation technology, the apparatus looks as if the apparatus started up from a shutdown state, called a cold boot. The apparatus, however, stores the register contents of a central processing unit (CPU) and a chip, and the contents of a volatile memory in hibernation data immediately before the shutdown. Consequently, if the hibernation data is restored in the register and the volatile memory, the operation state immediately before the shutdown is restored. Accordingly, as compared to the cold boot in which initialization of the hardware and the software is necessary, the startup time can be shortened.
The hibernation technology, however, requires generation of the hibernation data at the time of shutdown and write-back processing of the data in the register and memory at the time of startup. It takes time in some cases depending on the operation state of the apparatus.